viafb: Fix initialization error paths

Properly localize error cleanup, and make sure that the iomem regions are
unmapped if framebuffer initialization fails.

Reported-by: Bruno Prémont <bonbons@linux-vserver.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

1 files changed, 24 insertions, 11 deletions

diff --git a/drivers/video/via/via-core.c b/drivers/video/via/via-core.c
index 9929bb1549b6..188c0022dcb4 100644
--- a/drivers/video/via/via-core.c
+++ b/drivers/video/via/via-core.c
@@ -453,26 +453,40 @@ static int viafb_get_fb_size_from_pci(int chip_type)
  */
 static int __devinit via_pci_setup_mmio(struct viafb_dev *vdev)
 {
+        int ret;
         /*
-         * Hook up to the device registers.
+         * Hook up to the device registers.  Note that we soldier
+         * on if it fails; the framebuffer can operate (without
+         * acceleration) without this region.
          */
         vdev->engine_start = pci_resource_start(vdev->pdev, 1);
         vdev->engine_len = pci_resource_len(vdev->pdev, 1);
-        /* If this fails, others will notice later */
         vdev->engine_mmio = ioremap_nocache(vdev->engine_start,
                         vdev->engine_len);
-
+        if (vdev->engine_mmio == NULL)
+                dev_err(&vdev->pdev->dev,
+                                "Unable to map engine MMIO; operation will be "
+                                "slow and crippled.\n");
         /*
-         * Likewise with I/O memory.
+         * Map in framebuffer memory.  For now, failure here is
+         * fatal.  Unfortunately, in the absence of significant
+         * vmalloc space, failure here is also entirely plausible.
+         * Eventually we want to move away from mapping this
+         * entire region.
          */
         vdev->fbmem_start = pci_resource_start(vdev->pdev, 0);
-        vdev->fbmem_len = viafb_get_fb_size_from_pci(vdev->chip_type);
-        if (vdev->fbmem_len < 0)
-                return vdev->fbmem_len;
+        ret = vdev->fbmem_len = viafb_get_fb_size_from_pci(vdev->chip_type);
+        if (ret < 0)
+                goto out_unmap;
         vdev->fbmem = ioremap_nocache(vdev->fbmem_start, vdev->fbmem_len);
-        if (vdev->fbmem == NULL)
-                return -ENOMEM;
+        if (vdev->fbmem == NULL) {
+                ret = -ENOMEM;
+                goto out_unmap;
+        }
         return 0;
+out_unmap:
+        iounmap(vdev->engine_mmio);
+        return ret;
 }
 
 static void __devexit via_pci_teardown_mmio(struct viafb_dev *vdev)
@@ -572,12 +586,11 @@ static int __devinit via_pci_probe(struct pci_dev *pdev,
         viafb_int_init();
         via_setup_subdevs(&global_dev);
         /*
-         * Set up the framebuffer.
+         * Set up the framebuffer device
          */
         ret = via_fb_pci_probe(&global_dev);
         if (ret)
                 goto out_subdevs;
-
         return 0;
 
 out_subdevs: